Underground locations provide insights into geological processes and human history. Natural caves display limestone formations, stalactites, and subterranean rivers formed over thousands of years. Artificial sites include Roman catacombs, medieval cellars, and mining tunnels that document economic and social developments. This collection features prehistoric burial chambers with wall paintings, extensive cave systems with lakes and passages, and historical mines for salt, copper, or coal. Visitors can explore archaeological findings, mineral formations, and technical installations from earlier periods. Temperatures remain constant throughout the year, and many sites offer guided tours through their underground chambers.
